Make preallocated use AlignedType

Author: elichai

src/context.rs

@@ -233,7 +233,7 @@ unsafe impl<'buf> Context for AllPreallocated<'buf> {
 
 impl<'buf, C: Context + 'buf> Secp256k1<C> {
     /// Lets you create a context with preallocated buffer in a generic manner(sign/verify/all)
-    pub fn preallocated_gen_new(buf: &'buf mut [u8]) -> Result<Secp256k1<C>, Error> {
+    pub fn preallocated_gen_new(buf: &'buf mut [AlignedType]) -> Result<Secp256k1<C>, Error> {
         #[cfg(target_arch = "wasm32")]
         ffi::types::sanity_checks_for_wasm();
 
@@ -254,7 +254,7 @@ impl<'buf, C: Context + 'buf> Secp256k1<C> {
 
 impl<'buf> Secp256k1<AllPreallocated<'buf>> {
     /// Creates a new Secp256k1 context with all capabilities
-    pub fn preallocated_new(buf: &'buf mut [u8]) -> Result<Secp256k1<AllPreallocated<'buf>>, Error> {
+    pub fn preallocated_new(buf: &'buf mut [AlignedType]) -> Result<Secp256k1<AllPreallocated<'buf>>, Error> {
         Secp256k1::preallocated_gen_new(buf)
     }
     /// Uses the ffi `secp256k1_context_preallocated_size` to check the memory size needed for a context
@@ -284,7 +284,7 @@ impl<'buf> Secp256k1<AllPreallocated<'buf>> {
 
 impl<'buf> Secp256k1<SignOnlyPreallocated<'buf>> {
     /// Creates a new Secp256k1 context that can only be used for signing
-    pub fn preallocated_signing_only(buf: &'buf mut [u8]) -> Result<Secp256k1<SignOnlyPreallocated<'buf>>, Error> {
+    pub fn preallocated_signing_only(buf: &'buf mut [AlignedType]) -> Result<Secp256k1<SignOnlyPreallocated<'buf>>, Error> {
         Secp256k1::preallocated_gen_new(buf)
     }
 
@@ -316,7 +316,7 @@ impl<'buf> Secp256k1<SignOnlyPreallocated<'buf>> {
 
 impl<'buf> Secp256k1<VerifyOnlyPreallocated<'buf>> {
     /// Creates a new Secp256k1 context that can only be used for verification
-    pub fn preallocated_verification_only(buf: &'buf mut [u8]) -> Result<Secp256k1<VerifyOnlyPreallocated<'buf>>, Error> {
+    pub fn preallocated_verification_only(buf: &'buf mut [AlignedType]) -> Result<Secp256k1<VerifyOnlyPreallocated<'buf>>, Error> {
         Secp256k1::preallocated_gen_new(buf)
     }
 

src/lib.rs

@@ -151,7 +151,8 @@ pub use key::PublicKey;
 pub use context::*;
 use core::marker::PhantomData;
 use core::ops::Deref;
-use ffi::CPtr;
+use core::mem;
+use ffi::{CPtr, types::AlignedType};
 
 #[cfg(feature = "global-context")]
 pub use context::global::SECP256K1;
@@ -630,7 +631,10 @@ impl<C: Context> Secp256k1<C> {
 
     /// Returns the required memory for a preallocated context buffer in a generic manner(sign/verify/all)
     pub fn preallocate_size_gen() -> usize {
-        unsafe { ffi::secp256k1_context_preallocated_size(C::FLAGS) }
+        let word_size = mem::size_of::<AlignedType>();
+        let bytes = unsafe { ffi::secp256k1_context_preallocated_size(C::FLAGS) };
+
+        (bytes + word_size - 1) / word_size
     }
 
     /// (Re)randomizes the Secp256k1 context for cheap sidechannel resistance;
@@ -763,7 +767,7 @@ mod tests {
     use super::constants;
     use super::{Secp256k1, Signature, Message};
     use super::Error::{InvalidMessage, IncorrectSignature, InvalidSignature};
-    use ffi;
+    use ffi::{self, types::AlignedType};
     use context::*;
 
     macro_rules! hex {
@@ -840,10 +844,10 @@ mod tests {
 
     #[test]
     fn test_preallocation() {
-        let mut buf_ful = vec![0u8; Secp256k1::preallocate_size()];
-        let mut buf_sign = vec![0u8; Secp256k1::preallocate_signing_size()];
-        let mut buf_vfy = vec![0u8; Secp256k1::preallocate_verification_size()];
-//
+        let mut buf_ful = vec![AlignedType::zeroed(); Secp256k1::preallocate_size()];
+        let mut buf_sign = vec![AlignedType::zeroed(); Secp256k1::preallocate_signing_size()];
+        let mut buf_vfy = vec![AlignedType::zeroed(); Secp256k1::preallocate_verification_size()];
+
         let full = Secp256k1::preallocated_new(&mut buf_ful).unwrap();
         let sign = Secp256k1::preallocated_signing_only(&mut buf_sign).unwrap();
         let vrfy = Secp256k1::preallocated_verification_only(&mut buf_vfy).unwrap();